Since about 1976 the cutting of the fixed dimensions of frequently-used glass types has been based predominantly on so-called jumbo sizes (e.g. 6000×3210 mm). The raw product is delivered by HGV on large A-stands and deposited in packs on A-stands or L-stands in the glass plant by means of a gantry crane. From there the individual raw glass storage slab is tipped out of the pack using either the same gantry crane or other removal devices provided with vacuum suction elements and placed against the almost vertically-disposed vacuum suction elements of the tilting table. The suction elements are then tilted to the horizontal and thus also move the glass to the horizontal. New methods allow flat glass to be cut also in the vertical position. In the procedure usual up to now the glass is transported horizontally from the tilting table to the actual cutting table. There it is positioned roughly by lateral stops and finely in the longitudinal direction by sensors, and locked by being lowered on to the table. The cutting tables currently on the market have only one cutting head, which can be moved and positioned on a bridge. The bridge is also movable, so that each coordinate can be reached. The cutting head can be set to any desired angle. It is therefore possible to cut right-angled panes as well as rectilinear designs and completely free forms. The cutting plans are calculated on a computer (usually PC) by a cutting optimisation program and transferred to the machine control system via a network. As a rule, the computer of the machine control system is also able to carry out optimisations. A typical cutting plan for a raw glass slab 21 divided up in a characteristic manner is shown in FIG. 1.
The storage dimension first receives an initial cut in the transverse and longitudinal directions (zero cuts) which serve as reference straight lines. The cutting plan is then divided up briefly. The plan itself is first divided up transversely by x-cuts. The cross-cut strips thus produced are divided up again by y-cuts. Z-cuts may then be located between two y-cuts. So-called w-cuts may also occur theoretically, but generally do not lead to a further improvement in the proportion of cutting waste and therefore frequently are not generated at all in the cutting optimisation. The division described here has the advantage that automatic breaking can be carried out relatively simply.
The cut (better: notched) glass plate is transported onwards complete on to a series of breaking tables. The first breaking table has the function of breaking the x-cut. For this purpose the whole glass plate is either placed under tension on rollers, so that the x-cut is broken as it passes through, or it is broken by a breaking strip pressed against the glass from below. In this case, however, the glass must be briefly stopped in the correct position. The correct position is derived from the feed rate of the glass plate. In both methods, the panes are transported away at higher speed than the supply transport rate, so that a gap is produced between the cross-cut strips. On the last storage slab of an optimisation run a large residual plate is produced which must be removed from the flow via a further tilting table or manually, in some cases using a gantry crane. Another table diverts the glass flow away at a right angle. The breaking of the y-cuts is again carried out automatically, as described for the x-cuts, or manually. The glass flow is then again deflected through 90° and finally the z-cut is broken, again either automatically or manually. With individual designs the breaking is usually done manually.
After the breaking of the z-cuts the fixed dimensions are ready. They must then be moved back to the vertical, manually or automatically, and can then be sorted, either manually on fixed or movable A-stands, or automatically or manually in compartmented trucks. Fixed A-stands are then placed on mobile A-stands in the reverse sequence of production. The transport stands or compartmented trucks are supplied to the further processing operations (for example, insulating glass production, ESG production, grinding, drilling, etc.). At the processing lines the panes are unloaded manually or automatically. In the case of compartmented trucks it can be ensured that the removal sequence corresponds to an optimum production sequence of the following process.
EP 1 319 634 A1 describes a method and a device for dividing glass slabs into cuttings, the notched cross-cut strips being stored in an intermediate buffer and being supplied to a subsequent process as required. The structure of the intermediate buffer has the disadvantage that                for example, an average volume of 400 square metres of single glass must be completely cut to size;        a large amount of space is therefore required for storage;        the glass must wait a long time for further processing (e.g. a half-day);        a broken glass pane or a fast-tracked order in the following process can be cut only with a long time delay and outside the normal logistics.        
The only methods by which, at present, glass can be divided up vertically in practice are used when dividing laminated safety glass, in particular bullet-proof glass. Laminated safety glass with two panes can be achieved by simultaneously notching the upper and lower panes. However, breaking of the panes does not separate them, because a film is still bonded between the two panes. The glass is finally severed by heating and pulling apart the panes and cutting the film with a blade. With more than two panes this method fails because the inner pane cannot be notched. Cutting must then be done by sawing or water jet. This takes place as a rule in the (almost) vertical position using a water-rinsed diamond cutting disc. By now, two-pane safety glass panels are also severed vertically at cutting plants. When processing the glass in the vertical position there is the added difficulty that the glass panels must be rotated. The patent application EP 0 905 062 A1 describes the method for cutting, breaking, severing the film and rotating the sheet.
Further patents and patent applications (U.S. Pat. No. 4,871,104, DE 42 34 536 A1, EP 0 805 784 B1) relate to cutting in the vertical position. They describe cutting and breaking in isolation, but not the continuous logistics of the glass production sequence. Moreover, the methods described in these documents have not yet been commercialised.
A further method for severing bullet-proof glass in the horizontal plane and also in the vertical plane, and of severing especially thick glass, operates with the water jet, whereby a water jet containing extremely fine glass dust under extreme pressure and at high velocity severs the glass.
US 2005/0182506 A1 describes a glass cutting line with which continuous optimisation of the glass cuttings takes place.
The present situation in insulating glass manufacture is characterised by the fact that standard insulating glass no longer consists, as earlier, of two identical panes of 4 mm float glass but, in more than 90% of cases, has an asymmetrical structure. Whereas earlier computer-aided optimisations of 4 mm float glass produced waste proportions of 5%, and therefore savings of 10% in comparison to manual dividing of the glass, today only approximately 15% of waste is achieved again, even when using conventional software. The reason is that, as a result of the asymmetrical structure of the panes, each type of glass must be optimised and temporarily stored individually. Because the available space is limited, and, moreover, the ability to react to market requirements makes it necessary constantly to feed new orders into the production process, the result is that it has been usual up to now to optimise, cut and produce many individual production jobs (7 to 8 for a plant of typical size) per day. The small volume which can be optimised in each case explains the poor utilisation of material, the high number of remnants at the end of each job and for each type of glass, the high handling requirement for putting aside the remnants and the risk of scratching by this handling.